Hysteretic Behavior Of A New Type Of Self-centering Square Concretefilled Steel Tubular Column-H Beam Connection

Under the action of earthquake,beam-column joints are the weak links and key parts of frame structures.Once the brittle failure of the connection often leads to the structure after earthquake difficult to repair,serious will cause the structure collapse.With the development of seismic design concept,self-centering beam-and-column connections with post-earthquake reset function have become a research hotspot in the field of seismic engineering structures.A large number of experiments and numerical simulations have been carried out on the self-reset joints using steel strand and shape memory alloy,and the results show that such joints can achieve the dual functions of reset and energy consumption.In order to further expand the type of self-reset beam-column joints,based on the existing research,this paper proposes a new type of square steel tube concrete column-H-shaped steel beam joints combining disc springs and top and bottom curved ribbed angle steel joints.Experiments and numerical simulations were carried out,and a series of useful conclusions were drawn.The research work of this article is as follows:Designed and processed new self-reset square steel tube concrete column-H-shaped steel beam nodes with disc springs and prestressed steel rods,respectively In the loading test study,the mechanical properties of the nodes were evaluated from the aspects of hysteresis curve,skeleton curve,stiffness degradation,energy dissipation,and reset effect.(2)The traditional energy dissipation nodes of straight rib angle steel,arc stiffener angle steel,and self-reset beam-column joints with angle steel energy dissipation parts were designed,and the low-cycle reciprocating loading test was carried out.The focus is on the impact of setting the energy dissipation system and resetting system separately on the node.The influence of the stiffener form on the mechanical properties of the joints is compared.(3)ANSYS is used to establish a refined finite element model and perform finite element verification on all test specimens.(4)The finite element analysis of the parameters of the nodes using disc springs was carried out,and the effects of different initial prestress,different number of disc springs and different combinations of disc springs on the mechanical properties of the nodes were investigated.(5)The finite element analysis of the parameters of the nodes using steel strands and shape memory alloys was carried out,and the effects of different initial prestress on the mechanical properties of the nodes were investigated.